Biological photovoltaic device based on three-dimensional biological membrane anode and preparation method thereof

Abstract

The invention discloses a biological photovoltaic device based on a three-dimensional biological membrane anode and a preparation method thereof, and the preparation method comprises the following steps: carrying out mixed culture on a three-dimensional porous material and a microalgae liquid, adsorbing microalgae on the surface of the three-dimensional porous material, and growing the microalgae on the three-dimensional porous material through secreted EPS to obtain the three-dimensional biological membrane anode; electrically connecting the cathode and the three-dimensional biological membrane anode with the collector respectively, and sequentially laminating and assembling the cathode support frame, the cathode, the proton exchange membrane and the anode chamber; and fixing the three-dimensional biological membrane anode in an anode chamber, filling the anode chamber with a culture solution, and fixing an antibacterial waterproof breathable membrane at a breathable port of the anode chamber to obtain the biological photovoltaic device. Through the three-dimensional biological membrane anode, the attachment amount of microalgae is increased, and the resistance of the device is reduced; and transmembrane transfer of photoelectrons is carried out through external electricity activity of a biological membrane community to replace indirect electron transfer of exogenous toxic electrolyte, so that long-term self-sustaining operation of the device is facilitated, and the operation cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of biophotovoltaic technology, and in particular to a biophotovoltaic device based on a three-dimensional biofilm anode and a preparation method thereof. Background Art

[0002] Traditional photovoltaic power generation technology is mainly based on the photoelectric effect of semiconductor materials. The initial investment cost is high, and the photovoltaic panel manufacturing process is energy-intensive and polluting. The bio-photovoltaic system is mainly based on the photosynthesis of microalgae. The light system absorbs light energy, splits water to produce electrons, and transfers the electrons to the outside of the microalgae cells and is received by the anode. The electrons are then transferred to the cathode through an external circuit, and a reduction reaction occurs at the cathode, thereby forming an electric current. Photosynthetic microorganisms are renewable, the production process is low-cost, has no environmental pollution, and can fix carbon dioxide. It is a new type of solar power generation technology that is environmentally friendly and meets the goal of low-carbon development. In recent years, researchers have significantly improved the energy conversion efficiency of bio-photovoltaic systems by optimizing algae culture conditions, improving electrode materials, designing efficient device configurations, and reconstructing intracellular electron transfer pathways. As the technology matures, bio-photovoltaic power generation is expected to become an important part of the green energy field.

[0003] Existing microalgae bio-photovoltaic devices mainly adopt a dual-chamber structure design, which is divided into an anode chamber and a cathode chamber, separated by a proton exchange membrane in the middle, and the electrodes are arranged face to face. Photosynthetic microorganisms perform photosynthesis in the anode chamber, and the electrons generated by the light reaction reach the cathode through the anode and the wire. The generated protons are transferred to the cathode chamber through the proton exchange membrane, and then to the cathode, where they react with oxygen to generate water, thereby generating current.

[0004] Among them, the anode chamber is loaded with algae liquid and exogenous electron carriers such as quinone compounds and potassium ferrocyanide, and relies on exogenous electron carriers to transfer electrons. Although exogenous electron carriers can promote indirect electron transfer, they are generally biologically toxic and will inhibit the metabolic activity of photosynthetic microorganisms; at the same time, electrolytes need to be replenished regularly, and the maintenance cost is high. In addition, the sealed anode chamber is used to prevent contamination by miscellaneous bacteria, so that the oxygen produced by the photosynthesis of microalgae cannot be discharged in time. The accumulated oxygen not only competes for photoreaction electrons through the "oxygen electron-snatching" phenomenon, reduces the efficiency of electron transfer and causes photocurrent attenuation, but also inhibits the activity of the photosynthetic system due to excessive dissolved oxygen concentration, forms a feedback inhibition effect, and significantly reduces the light energy conversion efficiency of microalgae. Furthermore, two-dimensional anodes (such as stainless steel plates, copper plates, carbon paper, conductive glass, etc.) are generally used, with insufficient specific surface area, relatively smooth surface, and microalgae are not easy to attach, and there are insufficient attachment points. Finally, affected by the dual-chamber structure design and electrolyte characteristics, the internal resistance of the device is generally as high as kΩ to MΩ level, which causes significant energy loss, reduces energy conversion efficiency, and affects the stability of current output. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a biophotovoltaic device based on a three-dimensional biofilm anode and a preparation method thereof. Microalgae are adsorbed on a carrier by electrostatic adsorption, and attach and grow to the surface of the carrier by secreting extracellular secretions (EPS) during growth and metabolism to form a biofilm dominated by microalgae. The biofilm anode transfers photoelectrons across the membrane through the external electrical activity of the biofilm community, thereby replacing the indirect electron transfer method of adding exogenous toxic electrolytes, which is beneficial to the long-term self-sustaining operation of the device. A three-dimensional multi-porous material is used as a carrier to provide three-dimensional attachment points, and the attachment efficiency of microorganisms is improved by introducing oxygen-containing functional groups through modification.

[0006] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing a three-dimensional biofilm anode biophotovoltaic device, comprising the following steps: S1, immersing the three-dimensional multi-porous material in a strong acid to oxidize and introduce oxygen-containing functional groups, sterilizing and mixing with a microalgae solution for culture, the microalgae are adsorbed on the surface of the three-dimensional multi-porous material and the EPS secreted by the microalgae colonizes the three-dimensional multi-porous material through hydrogen bonds to form a microalgae biofilm, and a three-dimensional biofilm anode is obtained; S2, electrically connecting the cathode and the three-dimensional biofilm anode to the collector respectively, and sequentially stacking and assembling the cathode support frame, cathode, proton exchange membrane and anode chamber; S3. Fix the three-dimensional biofilm anode in the anode chamber and fill it with culture solution, then fix the antibacterial and waterproof breathable membrane to the breathable port of the anode chamber to obtain the three-dimensional biofilm anode-based biophotovoltaic device.

[0007] The present invention gets rid of the dependence on exogenous electron carriers. First, the microalgae are adsorbed on the carrier through electrostatic adsorption, and the extracellular secretions (EPS) secreted during the growth and metabolism of the microalgae cells are attached and grown on the surface of the carrier to form a biofilm community dominated by microalgae. The photoelectrons generated by the microalgae during photosynthesis are partially transferred to the extracellular environment under the light-dependent external electroactivity characteristics, and the biofilm anode transfers the photoelectrons across the membrane through the external electroactivity of the biofilm community, thereby replacing the indirect electron transfer method of adding exogenous toxic electrolytes, which is beneficial to the long-term self-sustaining operation of the device. At the same time, there is no need to replenish the electrolyte, thereby reducing the operating cost.

[0008] The present invention adopts three-dimensional porous materials as carriers, which have large specific surface area and provide three-dimensional attachment points. The surface is modified by strong acid oxidation to introduce oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH), which facilitates the attachment of EPS through hydrogen bonds, significantly improving the attachment efficiency of microorganisms. The attachment amount reaches 1-10 mg / cm 2 ), effectively solving the problem of insufficient attachment points of planar two-dimensional electrodes, and the resistance is reduced to 10-100Ω.

[0009] The present invention covers the ventilation port end of the anode chamber with an antibacterial and waterproof breathable membrane to form a "semi-open" structure. The antibacterial and waterproof breathable membrane prevents contamination by miscellaneous bacteria and promotes the circulation of oxygen in the anode chamber, discharges the oxygen generated by the photosynthesis of microalgae in time, and reduces the inhibitory effect of excessive oxygen on photosynthesis.

[0010] Furthermore, in S1, the three-dimensional multi-porous material is selected from aluminum wire windings, copper wire windings or titanium wire winding carbon fibers.

[0011] Furthermore, in S1, the strong acid is hydrochloric acid or nitric acid.

[0012] Further, in S1, the culturing is specifically: carrying out xh:xh light-dark cycle for 3-5 days at 20-25°C, wherein the light intensity is 40-60 μmol photons m -2 s -2 , x is 10-14. The light-dark cycle is more conducive to the growth of microalgae biofilm, the whole process is non-toxic, and the stress resistance and self-supporting structure of the biofilm improve the operation cycle and stability of the device.

[0013] Further, in S1, the OD of the microalgae solution is 620nm It is 0.3-1.0.

[0014] Furthermore, in S2, a step of ultraviolet sterilization is also included before stacking and assembling.

[0015] Furthermore, in S3, the pore size of the antibacterial, waterproof and breathable membrane is 0.2-0.5 μm, and the oxygen permeability is ≥8000 cm 3 / (m 2 ·24h·bar), the interception rate of microorganisms with a diameter ≥ 0.22 μm is ≥ 90%.

[0016] Furthermore, the edge sealing is achieved between the anode chamber and the proton exchange membrane, and between the cathode support frame and the cathode by assembling a gasket with a hollow middle. Preferably, the gasket is made of PDMS (polydimethylsiloxane).

[0017] The second aspect of the present invention provides a biophotovoltaic device based on a three-dimensional biofilm anode, which is obtained by the preparation method described in the first aspect, and includes an anode chamber, wherein an antibacterial, waterproof and breathable membrane and a proton exchange membrane are respectively arranged at the openings at both ends of the anode chamber, and the proton exchange membrane is stacked with the cathode and fixed by a cathode support frame, and the cathode support frame is connected to the anode chamber through a connecting piece, and a three-dimensional biofilm anode is fixed in the anode chamber and filled with culture fluid, and the three-dimensional biofilm anode and cathode are respectively connected to a collector.

[0018] Furthermore, the three-dimensional biofilm anode includes a three-dimensional multi-porous material carrier and a microalgae biofilm planted on the carrier.

[0019] Furthermore, the side of the cathode away from the proton exchange membrane is in contact with the air through a through hole located in the cathode support frame.

[0020] Furthermore, it also includes two gaskets with hollowed-out middles, which are installed between the anode chamber and the proton exchange membrane and between the cathode support frame and the cathode.

[0021] The present invention is based on a three-dimensional biofilm anode biophotovoltaic device that generates electrons and protons through photosynthesis of microalgae. Photoelectrons are transferred from the microalgae cells to the outside of the cells, through the anode and the collector to the cathode. Protons are transferred to the cathode through the proton exchange membrane and react with oxygen in the air: O 2 +4H + +4e - →2H 2 O, thus forming electric current. The device can convert solar energy into electrical energy, realizing the utilization of solar energy and the fixation of carbon.

[0022] Beneficial effects of the present invention: The present invention adsorbs microalgae onto a carrier through electrostatic adsorption, and the microalgae are attached and grown on the surface of the carrier through the EPS secreted by the microalgae to form a biofilm community. The transmembrane transfer of photoelectrons is carried out through the external electrical activity of the biofilm community, replacing the indirect electron transfer method of adding exogenous toxic electrolytes, which is beneficial to the long-term self-sustaining operation of the device. At the same time, there is no need to replenish electrolytes, thereby reducing operating costs.

[0023] The present invention adopts three-dimensional multi-porous materials as carriers, which have a large specific surface area and provide three-dimensional attachment points. It also introduces oxygen-containing functional groups through surface modification, which significantly improves the attachment efficiency of microorganisms. The attachment amount is 5-10 times that of two-dimensional electrodes, effectively solving the problem of insufficient attachment points of planar two-dimensional electrodes, and the resistance is reduced to 10-100Ω.

[0024] The present invention covers the ventilation port end of the anode chamber with an antibacterial and waterproof breathable membrane to form a "semi-open" structure. The antibacterial and waterproof breathable membrane prevents contamination by miscellaneous bacteria and promotes the circulation of oxygen in the anode chamber, discharges the oxygen generated by the photosynthesis of microalgae in time, and reduces the inhibitory effect of excessive oxygen on photosynthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a schematic diagram of the structure of a three-dimensional biofilm anode biophotovoltaic device according to the present invention; Explanation of the numbers in the figure: 1. anode chamber, 2. antibacterial, waterproof and breathable membrane, 3. proton exchange membrane, 4. cathode, 5. cathode support frame, 6. connector, 7. three-dimensional biofilm anode, 8. collector, 9. gasket. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] This embodiment relates to a method for preparing a three-dimensional biofilm anode biophotovoltaic device, comprising the following steps: S1, immersing the three-dimensional multi-porous material in a strong acid to oxidize and introduce oxygen-containing functional groups, sterilizing and mixing with a microalgae solution for culture, the microalgae are adsorbed on the surface of the three-dimensional multi-porous material and the EPS secreted by the microalgae colonizes the three-dimensional multi-porous material through hydrogen bonds to form a microalgae biofilm, and a three-dimensional biofilm anode is obtained; S2, electrically connecting the cathode and the three-dimensional biofilm anode to the collector respectively, and sequentially stacking and assembling the cathode support frame, cathode, proton exchange membrane and anode chamber; S3. Fix the three-dimensional biofilm anode in the anode chamber and fill it with culture solution, then fix the antibacterial and waterproof breathable membrane to the breathable port of the anode chamber to obtain the three-dimensional biofilm anode-based biophotovoltaic device.

[0029] In this embodiment, the microalgae are adsorbed on the carrier by electrostatic adsorption, and the EPS secreted during the growth and metabolism of the microalgae cells is attached to the surface of the carrier to form a biofilm community dominated by microalgae; the photoelectrons generated by the microalgae during photosynthesis are partially transferred to the extracellular environment under the light-dependent external electroactivity characteristics, and the biofilm anode transfers the photoelectrons across the membrane through the external electroactivity of the biofilm community, thereby replacing the indirect electron transfer method of adding exogenous toxic electrolytes, which is beneficial to the long-term self-sustaining operation of the device; at the same time, there is no need to replenish electrolytes, reducing operating costs. The three-dimensional multi-porous material is used as a carrier, which has a large specific surface area and provides three-dimensional attachment points. The surface is modified by strong acid oxidation, and oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH) are introduced to facilitate the attachment of EPS through hydrogen bonds, which significantly improves the attachment efficiency of microorganisms. The attachment amount is 5-10 times that of the two-dimensional electrode, effectively solving the problem of insufficient attachment points of the planar two-dimensional electrode, and the resistance is reduced to 10-100Ω. The air outlet of the anode chamber is covered with an antibacterial and waterproof breathable membrane to form a "semi-open" structure. The antibacterial and waterproof breathable membrane prevents contamination by foreign bacteria, promotes the circulation of oxygen in the anode chamber, and discharges the oxygen produced by the photosynthesis of microalgae in time, reducing the inhibitory effect of excessive oxygen on photosynthesis.

[0030] As a preferred embodiment, in S1, the strong acid is hydrochloric acid or nitric acid; the OD of the microalgae solution is 620nm The three-dimensional multi-porous material is selected from aluminum wire winding, copper wire winding or titanium wire winding carbon fiber; the culture is specifically: xh: xh light-dark cycle for 3-5 days at 20-25°C, wherein the light intensity is 40-60 μmol photonsm -2 s -2 , x is 10-14. The light-dark cycle is more conducive to the growth of microalgae biofilm, the whole process is non-toxic, and the stress resistance and self-supporting structure of the biofilm improve the operation cycle and stability of the device.

[0031] As a preferred embodiment, in S2, a step of ultraviolet sterilization is also included before stacking and assembling.

[0032] As a preferred embodiment, in S3, the pore size of the antibacterial, waterproof and breathable membrane is 0.2-0.5 μm, and the oxygen permeability is ≥8000 cm 3 / (m 2 ·24h·bar), the interception rate of microorganisms with a diameter ≥ 0.22 μm is ≥ 90%.

[0033] As a preferred embodiment, edge sealing is achieved between the anode chamber and the proton exchange membrane, and between the cathode support frame and the cathode by assembling a PDMS gasket with a hollow center.

[0034] Another embodiment provides a three-dimensional biofilm anode biophotovoltaic device, such as Figure 1 As shown, it includes an anode chamber 1, and an antibacterial, waterproof and breathable membrane 2 and a proton exchange membrane 3 are respectively arranged at the openings at both ends of the anode chamber 1. The proton exchange membrane 3 and the cathode 4 are stacked and fixed by a cathode support frame 5. The cathode support frame 5 is connected to the anode chamber 1 through a connector 6. A three-dimensional biofilm anode 7 is fixed in the anode chamber 1 and filled with culture fluid. The three-dimensional biofilm anode 7 and the cathode 4 are respectively connected to a collector 8. This embodiment is based on a three-dimensional biofilm anode 7. The biophotovoltaic device generates electrons and protons through the photosynthesis of microalgae. Photoelectrons are transferred from the microalgae cells to the outside of the cells, through the anode and the collector 8 to the cathode 4, and protons are transferred to the cathode 4 through the proton exchange membrane 3, and react with oxygen in the air: O 2 +4H + +4e - →2H 2 O, thus forming electric current. The device can convert solar energy into electrical energy, realizing the utilization of solar energy and the fixation of carbon.

[0035] Specifically, the three-dimensional biofilm anode 7 includes a three-dimensional multi-porous material carrier and a microalgae biofilm implanted on the carrier; the side of the cathode 4 away from the proton exchange membrane 3 is in contact with the air through the through holes located in the cathode support frame 5.

[0036] As a preferred embodiment, two gaskets 9 with hollowed-out middle portions are further included, and the two gaskets 9 are assembled between the anode chamber 1 and the proton exchange membrane 3 and between the cathode 4 support frame and the cathode 4 .

[0037] Example 1

[0038] This embodiment provides a method for preparing a three-dimensional biofilm anode biophotovoltaic device, comprising the following steps: (1) Preparation of carbon fiber brush three-dimensional biofilm anode Mesophase pitch-based carbon fibers were selected and soaked in acetone for 48 hours, then rinsed with deionized water to remove chemical residual impurities on the surface of the carbon fibers, and the treated carbon fibers were wound with titanium wires with a diameter of 0.8 mm and a length of 5 cm to finally make carbon fiber brushes. The carbon fiber brushes were immersed in a 1.0 mol / L HCl solution for 2 hours to introduce hydroxyl (-OH) and carboxyl (-COOH) oxygen-containing functional groups through strong acid oxidation; The carbon fiber brush was sterilized by high pressure (121°C, 15 psi, 15 min) and placed in a sterilized glass bottle. 100 mL of standardized OD 620nm= 1.0, and centrifuge the culture solution of Chlorella exponential phase at low speed (500 r / min, 1 min) to obtain the supernatant and the concentrated microalgae solution below. Use a pipette to remove the supernatant, add the sterilized culture medium, gently shake the centrifuge tube and use a pipette to gently blow the algae solution below to mix it evenly, then pour the algae solution into a glass bottle for sedimentation and place it under a cool white fluorescent light (40 μmol photons m -2 s -2 ) irradiation, 12:12h light-dark cycle for 3 days to form a biofilm, and a carbon fiber brush three-dimensional biofilm anode was obtained, with a microalgae attachment amount of 60mg / cm 2 .

[0039] (2) Cathode preparation Cut 45*45 mm carbon paper with a thickness of 0.2 mm, and soak the electrode in 1.0 mol / L NaOH to remove impurities on the electrode surface. Take out the electrode, rinse it with a large amount of deionized water until the last rinse is neutral to remove residual NaOH, and then dry the electrode.

[0040] (3) Preparation of antibacterial, waterproof and breathable membrane Cut a 30 mm diameter antibacterial, waterproof and breathable membrane with a pore size of 0.45 μm, use anhydrous ethanol to ultrasonically clean it for 5 minutes to remove surface impurities, and dry it for later use.

[0041] (4) Electrically connect the three-dimensional biofilm anode and cathode to the collector.

[0042] (5) Sterilize the anode chamber, gasket, and cathode support frame under a 100 W ultraviolet lamp for 60 min.

[0043] (6) Assembly The cathode support frame, PDMS gasket, cathode, proton exchange membrane, PDMS gasket, and anode chamber are stacked from bottom to top in this order and tightened with screws and nuts. The elasticity of PDMS is used to achieve sealing in the middle to prevent leakage of internal liquid and assist in positioning each functional layer.

[0044] (7) Anode chamber filling The carbon fiber brush three-dimensional biofilm anode was fixed to the anode chamber, filled with culture medium, and finally covered with an antibacterial, waterproof and breathable membrane to obtain a three-dimensional biofilm anode biophotovoltaic device. -2 s -2 The detection resistance is only about 45Ω under light.

[0045] Example 2

[0046] This embodiment provides a method for preparing a three-dimensional biofilm anode biophotovoltaic device, comprising the following steps: (1) Preparation of carbon fiber brush three-dimensional biofilm anode A fluffy mass of interwoven long and thin aluminum wires was used as a three-dimensional porous material, which was immersed in a 2 mol / L NaOH solution for etching to remove surface dirt, and then immersed in a concentrated nitric acid solution for 1 hour to introduce hydroxyl (-OH) and carboxyl (-COOH) oxygen-containing functional groups through strong acid oxidation. After high-pressure sterilization (121°C, 15 psi, 15 min), place in a sterilized glass bottle. Take 100 mL of standardized OD 620nm =1.0, and centrifuge the culture solution of Chlorella exponential phase at low speed (500 r / min, 1 min) to obtain the supernatant and the concentrated microalgae solution below. Use a pipette to remove the supernatant, add the sterilized culture medium, gently shake the centrifuge tube and use a pipette to gently blow the algae solution below to mix it evenly, then pour the algae solution into a glass bottle for sedimentation and place it under a cool white fluorescent light (60 μmol photons m -2 s -2 ) irradiation, 12:12h light-dark cycle for 3 days to form a biofilm, and a carbon fiber brush three-dimensional biofilm anode was obtained, with a microalgae attachment amount of 70mg / cm 2 .

[0047] (2) Cathode preparation Cut 45*45 mm carbon paper with a thickness of 0.2 mm, and soak the electrode in 1.0 mol / L NaOH to remove impurities on the electrode surface. Take out the electrode, rinse it with a large amount of deionized water until the last rinse is neutral to remove residual NaOH, and then dry the electrode.

[0048] (3) Preparation of antibacterial, waterproof and breathable membrane Cut a 30 mm diameter antibacterial, waterproof and breathable membrane with a pore size of 0.2 μm, use anhydrous ethanol to ultrasonically clean it for 5 minutes to remove surface impurities, and dry it for later use.

[0049] (4) Electrically connect the three-dimensional biofilm anode and cathode to the collector.

[0050] (5) Sterilize the anode chamber, gasket, and cathode support frame under a 100 W ultraviolet lamp for 60 min.

[0051] (6) Assembly The cathode support frame, PDMS gasket, cathode, proton exchange membrane, PDMS gasket, and anode chamber are stacked from bottom to top in this order and tightened with screws and nuts. The elasticity of PDMS is used to achieve sealing in the middle to prevent leakage of internal liquid and assist in positioning each functional layer.

[0052] (7) Anode chamber filling The carbon fiber brush three-dimensional biofilm anode was fixed to the anode chamber, filled with culture medium, and finally covered with an antibacterial, waterproof and breathable membrane to obtain a three-dimensional biofilm anode biophotovoltaic device. -2 s -2 The resistance under light is only about 80Ω.

[0053] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a three-dimensional biofilm anode biophotovoltaic device, characterized in that: The steps include: S1, immersing the three-dimensional multi-porous material in a strong acid to oxidize and introduce oxygen-containing functional groups, sterilizing and mixing with a microalgae solution for culture, the microalgae are adsorbed on the surface of the three-dimensional multi-porous material and the EPS secreted by the microalgae colonizes the three-dimensional multi-porous material through hydrogen bonds to form a microalgae biofilm, and a three-dimensional biofilm anode is obtained; S2, electrically connecting the cathode and the three-dimensional biofilm anode to the collector respectively, and sequentially stacking and assembling the cathode support frame, cathode, proton exchange membrane and anode chamber; S3. Fix the three-dimensional biofilm anode in the anode chamber and fill it with culture solution, then fix the antibacterial and waterproof breathable membrane to the breathable port of the anode chamber to obtain the three-dimensional biofilm anode-based biophotovoltaic device.

2. The method for preparing a three-dimensional biofilm anode biophotovoltaic device according to claim 1, characterized in that: In S1, the three-dimensional multi-porous material is selected from aluminum wire windings, copper wire windings or titanium wire winding carbon fibers.

3. The method for preparing a three-dimensional biofilm anode biophotovoltaic device according to claim 1, characterized in that: In S1, the culture is specifically carried out under the conditions of 20-25°C with a light-dark cycle of xh:xh for 3-5 days, wherein x is 10-14 and the light intensity is 40-60 μmol photons m -2 s -2 .

4. The method for preparing a three-dimensional biofilm anode biophotovoltaic device according to claim 1, characterized in that: In S1, the OD of the microalgae solution 620nm It is 0.3-1.

0.

5. The method for preparing a three-dimensional biofilm anode biophotovoltaic device according to claim 1, characterized in that: In S3, the pore size of the antibacterial, waterproof and breathable membrane is 0.2-0.5 μm, and the oxygen permeability is ≥8000 cm 3 / (m 2 ·24h·bar), the interception rate of microorganisms with a diameter ≥ 0.22 μm is ≥ 90%.

6. The method for preparing a three-dimensional biofilm anode biophotovoltaic device according to claim 1, characterized in that: The edge sealing is achieved between the anode chamber and the proton exchange membrane, and between the cathode support frame and the cathode by assembling a gasket with a hollow middle portion.

7. A three-dimensional biofilm anode biophotovoltaic device, obtained by the preparation method according to any one of claims 1 to 6, characterized in that: It includes an anode chamber, wherein an antibacterial, waterproof and breathable membrane and a proton exchange membrane are respectively arranged at the openings at both ends of the anode chamber, the proton exchange membrane and the cathode are stacked and fixed by a cathode support frame, the cathode support frame is connected to the anode chamber through a connector, a three-dimensional biofilm anode is fixed in the anode chamber and filled with culture fluid, and the three-dimensional biofilm anode and cathode are respectively connected to a collector.

8. The three-dimensional biofilm anode biophotovoltaic device according to claim 7, characterized in that: The three-dimensional biofilm anode comprises a three-dimensional multi-porous material carrier and a microalgae biofilm attached to the carrier.

9. The method for preparing a three-dimensional biofilm anode biophotovoltaic device according to claim 7, characterized in that: The side of the cathode away from the proton exchange membrane is in contact with the air through the through holes in the cathode support frame.

10. The three-dimensional biofilm anode biophotovoltaic device according to claim 7, characterized in that: The invention also comprises two gaskets with hollowed-out middle parts, which are assembled between the anode chamber and the proton exchange membrane and between the cathode support frame and the cathode.

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